Wall Street rethinks blockchain projects as euphoria meets reality

Re:Wall Street rethinks blockchain projects as euphoria meet... by throwawaylolx on Thursday March 29, 2018 @12:39PM (#16708469)

It has always been the longest valid chain though. If miners were to introduce double-spending transactions in a block, full nodes would--by default--reject the blocks, regardless of how much work the chain contains. This also highlights why miners don't control the network and never had.

[ Parent | on HN ]

Re:Wall Street rethinks blockchain projects as euphoria meet... by alexbeloi on Thursday March 29, 2018 @01:32PM (#16709036)

I'm no expert so bear with me.

My understanding is that the danger of miner control is not "double-spending" but making multiple spends and being able to pick the most favorable one after the fact.

As a non-controller if you try to double-spend, you can't know which one of your attempted transactions will be recorded in the ledger and which will be rejected. As a 51% controlling miner, you can choose the 'correct' transaction.

This allows the 51% controlling miner to engage in futures arbitrage.

[ Parent | on HN ]

Re:Wall Street rethinks blockchain projects as euphoria meet... by throwawaylolx on Thursday March 29, 2018 @01:57PM (#16709328)

Double-spending just means spending the same output in multiple transactions--there are many ways to perform a double-spend attack. Your interpretation of a 51% attack is correct.

If it wasn't clear, my comment was referring to a double-spend that would result in an invalid block i.e. both transactions are on the same chain. I simply used an example to argue that it's always been the case that invalid chains are rejected by honest nodes.

[ Parent | on HN ]